Lecture 3 : Determinants of Protein Structure Flashcards
1
Q
What is the primary structure of a protein
A
- Sequence of amino acids in a polypeptide chain
- linked by peptide bonds
2
Q
What is the secondary structure of a protein
A
- Folding of the polypeptide chain
- Can form α-helices or β-pleated sheets
- HYDROGEN BONDS form between carbonyl oxygen and amide hydrogen of the peptide chains
3
Q
Tertiary Structure of Proteins
A
- 3D folding of whole chain
- Contains hydrogen bonding
- Ionic bonding (from transfer from H on COOH to NH2
- Hydrophobic interactions
- Disulphide bridges
4
Q
Quaternary Structure of Proteins
A
- Assembly of the polypeptide subunits into a protein complex
5
Q
What do hydrophobic associations do to a protein?
A
- Non-polar amino acid side chains repelled by water
- They cluster at the center of proteins
- Hydrophobic core created
6
Q
What can cause denaturation of a protein?
A
Temp changes - hydrogen bonds and other bonds disrupted which hold proteins together
pH changes - Changing pH alters the charge of amino acids and disrupts ionic bonds
Salts - Can disrupt hydrogen bonding and hydrophobic effect
None of these alter primary structure however
7
Q
How do van der waals forces affect protein structure
A
- Electron cloud around atoms constantly fluctuate
- Small charge differences induce temporary dipoles in adjacent atoms
- Significant in maintaining protein structure
8
Q
What is the 2nd law of thermodynamics?
A
Universe is always moving towards a greater entropy (more disorder)
9
Q
What is gibbs free energy equation
A
